JP6309498B2 - Capacitance detection pressure switch and pressure sensor - Google Patents

Description

  The present invention relates to a capacitance detection type pressure switch and a pressure sensor, and more particularly, to a capacitance detection type pressure switch and a pressure sensor using a diaphragm as one electrode.

  2. Description of the Related Art A diaphragm type pressure switch and a sensor for detecting the pressure of a working medium are known when controlling systems for air conditioning, air conditioning, automobiles, and industrial devices. A diaphragm type pressure switch is known as a contact type pressure switch. However, in a contact type pressure switch, there is a possibility that a continuity failure may occur due to foreign matter (insulator) being caught between the contacts. Therefore, contactless pressure switches and pressure sensors such as capacitance detection type, light detection type, magnetic detection type, and strain detection type are also used.

JP 2013-171614 A JP-A-8-82564 JP 2013-537972 A

  A hydraulic switch module including a plurality of contact-type hydraulic switches, a housing, a connection circuit, a plate member, and the like is also known in order to detect a plurality of hydraulic pressures as described in the cited document 1.

  Among contactless pressure switches, capacitance detection pressure switches and pressure sensors use a metal diaphragm as one electrode, and a fixed electrode provided on the atmospheric pressure side of the diaphragm via an insulating material It is also known that the pressure of the working medium is detected by detecting the change in the capacitance between the two electrodes with the other electrode as the other electrode.

  In the cited document 2, a movable electrode provided on a diaphragm, a fixed electrode disposed with a predetermined gap with respect to the movable electrode in a space separated from one space, and a surface of at least one of the electrodes An insulating layer provided and a detecting means for detecting the capacitance between both electrodes, and a capacitance detection type in which an ON region or an OFF region of the switch is separately provided in a region before and after the electrodes are in contact with each other. A pressure switch is disclosed.

  Cited Document 3 is a pressure gauge applied to blood pressure measurement, and includes an electrode portion and an elastic deformation portion provided on an outer periphery in the radial direction, and the electrode portion and the elastic deformation portion are integrally connected. When the stress is received in the axial direction, the elastically deforming portion can be deformed correspondingly, and pressure using a capacitive pressure sensor including a movable electrode device that moves the electrode portion along the axial direction. Totals are disclosed.

  In the capacitance detection type pressure switch as described above, depending on the connection method of the diaphragm used as one of the electrodes and the signal line for outputting a signal from the diaphragm, the pressure-displacement characteristic of the diaphragm, that is, the diaphragm There is a problem of affecting the operating characteristics. Further, since the diaphragm is deformed minutely, there is a problem that it is difficult to ensure stable conduction between the diaphragm and the signal line.

  Therefore, the object of the present invention is to secure stable conduction without affecting the operating characteristics of the diaphragm with respect to the connection between the diaphragm used as one of the electrodes and the signal line for detecting the signal from the diaphragm. An electrostatic capacitance detection type pressure switch and a pressure sensor are provided.

In order to solve the above-mentioned problem, the capacitance detection type pressure switch of the present invention is displaced according to the fluctuation of the pressure of the working medium supplied from the pipe line, and the pressure of the working medium from the pipe line is set. When the pressure is less than the value, it forms a shape that bulges downward, and when the pressure of the working medium from the pipe line exceeds a set value, the shape that bulges downward due to the pressure of the working medium bulges upward. A diaphragm that performs a snap action, reversibly reversing into an elliptical shape, a movable electrode that is electrically connected to the diaphragm, a fixed electrode that is provided on the atmospheric pressure side of the diaphragm facing the conduit, and the fixed An insulating coating for ensuring insulation between the electrode and the diaphragm; the diaphragm is displaced by a change in pressure of the working medium; and the displacement is connected to the diaphragm connected to the movable electrode. In the capacitance detection type pressure switch configured to detect a change in capacitance between the diaphragm and the fixed electrode and detect the pressure of the working medium based on the change in capacitance, the diaphragm An electrode contact portion for connecting the movable electrode, which is at least one protrusion extending outwardly, is formed on a part of the outer periphery of the electrode.

In addition, the electrode contact portion is provided with a through hole in the central portion, and at least one chamfer is provided on one side, and is formed into a shape that is caulked with the movable electrode. Also good.
Moreover, the thin part is formed in the base vicinity of the said electrode contact part , and it is good also as what is formed in the shape spot-welded with the said movable electrode.
Moreover, the thin part is formed in the base vicinity of the said electrode contact part , and it is good also as what is formed in the shape welded with the said movable electrode.
The tip of the electrode contact portion may be formed with a projection shape bent 90 degrees from the horizontal plane at the tip, and the electrode contact portion may be formed in a shape that fits with the movable electrode.
The electrode contact portion may be formed in a disc spring shape in which a leaf spring is provided on the outer periphery of the diaphragm, and connected to the movable electrode by the elastic force of the disc spring.

  According to the capacitance detection type pressure switch and pressure sensor of the present invention, the connection between the diaphragm used as one of the electrodes and the signal line for detecting the signal from the diaphragm affects the operating characteristics of the diaphragm. Therefore, stable conduction can be ensured.

It is a figure which shows the structure of the electrostatic capacitance detection type pressure switch by a prior art using a general disk-shaped diaphragm. It is a block diagram of an electrostatic capacitance detection circuit. FIG. 3 (a) is a diagram showing a comparison of characteristics when a contact load is applied between a disk-shaped diaphragm according to the prior art and the diaphragm of the capacitance detection type pressure switch of the present invention. FIG. 3B is a diagram showing deformation when a contact load is applied, and FIG. 3C is a diagram showing a stress distribution when the contact load is applied. FIG. 4A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm formed into a shape in which the electrode contact portion is crimped, 4B is a cross-sectional view taken along IVb-IVb in FIG. 4A, and FIG. 4C is an enlarged view of both the movable electrode and the electrode contact portion, and FIG. ) Is an enlarged view showing a state in which the movable electrode is inserted into the electrode contact portion, and FIG. 4E is an enlarged view showing a state in which the movable electrode is crimped to the electrode contact portion. . FIG. 5A is a diagram showing a reference example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm formed in a shape in which the electrode contact portion is soldered. 5B is a cross-sectional view taken along line Vb-Vb in FIG. 5A, and FIG. 5C is an enlarged view of both the movable electrode and the electrode contact portion. FIG. 5D is an enlarged view showing a state where the movable electrode is inserted into the electrode contact portion, and FIG. 5E is an enlarged view showing a state where the movable electrode is soldered to the electrode contact portion. is there. FIG. 6A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm formed in a shape in which the electrode contact portion is spot-welded, 6B is a cross-sectional view taken along line VIb-VIb in FIG. 6A, and FIG. 6C is an enlarged view of both the movable electrode and the electrode contact portion. ) Is an enlarged view showing a state in which the movable electrode is in contact with the electrode contact portion, and FIG. 6 (e) is an enlarged view showing a state in which the movable electrode is spot welded to the electrode contact portion. FIG. 6 (f) is an enlarged view showing a state where the movable electrode having a shape in which the tip is not bent is laser-welded to the electrode contact portion. Fig.7 (a) is a figure which shows an example of the shape of the diaphragm of the electrostatic capacitance detection type pressure switch of this invention, Comprising: It is a top view of the diaphragm formed in the shape by which an electrode contact part is connector-fitted. 7B is a cross-sectional view taken along the line VIIb-VIIb in FIG. 7A, and FIG. 7C is a cross-sectional view taken along the line VIIc-VIIc in FIG. 7A. FIG. 8A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and a plurality of plate spring-shaped electrode contact portions constituting a disc spring shape on the outer periphery of the diaphragm. It is a top view of the diaphragm formed, FIG.8 (b) is sectional drawing shown to VIIIb-VIIIb of Fig.8 (a). It is a figure which shows the structure of the electrostatic capacitance detection type pressure switch which concerns on one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
First, a capacitance detection type pressure switch according to the prior art will be described.
FIG. 1 is a diagram showing a configuration of a capacitance detection type pressure switch 100 according to the prior art using a general disk-shaped diaphragm 111.

  In FIG. 1, a pressure switch 100 is a working medium supply assembly having a conduit 11 for supplying working medium pressure for air conditioning, air conditioning, automobile and industrial equipment, and an O-ring 12 for sealing the working medium pressure. 10 to be used. The pressure switch 100 may be connected to a joint pipe or the like by removing a support member 131 and the like which will be described later.

  The pressure switch 100 includes a diaphragm assembly 110, a capacitance detection unit 120, and a fixing unit 130 that holds the diaphragm assembly 110 and the capacitance detection unit 120 and fixes them to the working medium supply assembly 10.

  The diaphragm assembly 110 includes a diaphragm 111 that is displaced according to a change in pressure of the working medium supplied from the pipe 11, an O-ring 112 that is disposed on the pipe 11 side of the diaphragm 111 and seals the working medium, and an O-ring. 112, which is in close contact with 112 and seals the working medium.

  The diaphragm 111 is a capacitance detection type pressure switch that detects a variation in capacitance between the diaphragm 111 and the fixed electrode 122 that is displaced due to a variation in pressure of the working medium, and based on the variation in capacitance. In order to detect the displacement of 111 and to detect the pressure of the working medium supplied from the pipe line 11 by the displacement of the diaphragm 111, a metal one is mainly used. In addition, the diaphragm 111 is mainly made of a metal having a reversing action, that is, a spring property that performs a snap action. However, when this configuration is applied to a pressure sensor that outputs a pressure measurement value, a snap action is used. Do not use diaphragms. When the pressure of the working medium from the pipe line 11 is less than the set value, the diaphragm 111 that performs the snap action has a shape that swells downward, and when the pressure of the working medium from the pipe line 11 exceeds the set value. By the pressure of the working medium, the shape swelled downward is reversibly reversed to the shape swelled upward.

  The O-ring 112 is disposed in a recess 131d provided around the opening 131a of the support member 131, and seals the working medium between the support member 131 and the diaphragm 111 together with a diaphragm 113 described later.

  The diaphragm 113 is affixed to the side of the duct 11 of the diaphragm 111, is displaced together with the diaphragm 111, is in close contact with the O-ring 112, and maintains airtightness on the working medium side.

  The electrostatic capacitance detection unit 120 is attached to the movable electrode 121 electrically connected to a part of the diaphragm 111, the fixed electrode 122 provided on the atmospheric pressure side of the diaphragm 111, and the diaphragm 111 side of the fixed electrode 122. The insulating coating 123 includes a capacitance detection IC 124 that is electrically connected to the movable electrode 121 and the fixed electrode 122 via the lead wire 125 and detects the capacitance between the diaphragm 111 and the fixed electrode 122.

  The movable electrode 121 is a metal component that is electrically connected to, for example, the outer peripheral portion of the metal diaphragm 111 that is less movable. The movable electrode 121 is connected to the capacitance detection IC 124 via the lead wire 125, whereby the diaphragm 111 forms one electrode of a capacitor in capacitance detection. The movable electrode 121 may have an annular shape that contacts the entire outer periphery of the diaphragm 111, or most of the outer periphery of the diaphragm 111 is covered with a resin stopper, and the movable electrode 121 is disposed on a part thereof. Further, it may be connected to the metal diaphragm 111 or other shapes.

  The fixed electrode 122 is a metal part having a shape that covers the atmospheric pressure side of the diaphragm 111 without contacting the diaphragm 111. The fixed electrode 122 is connected to the capacitance detection IC 124 via the lead wire 125, whereby the fixed electrode 122 forms the other electrode of the capacitor in capacitance detection. The shape of the fixed electrode 122 may be any shape that can be electrically connected to the capacitance detection IC 124 and can form the other electrode of the capacitor, such as a flat plate shape or a concave shape.

  The insulating film 123 is located between the diaphragm 111 and the fixed electrode 122 and plays a role of a capacitor dielectric in electrostatic capacitance detection. For this reason, since the capacitance of the insulating coating 123 changes according to the material and thickness, the material and thickness are selected according to the circuit configuration of the capacitance detection circuit 200 described later. In order to prevent the fixed electrode 122 and the diaphragm 111 from coming into contact with each other, the insulating coating 123 may use an impact absorbing material such as rubber or polyimide film, or may be insulated by sputtering, CVD, PVD, or the like. It may be formed. Further, although the insulating coating 123 is affixed to the surface of the fixed electrode 122, it may be affixed to the diaphragm 111.

  The capacitance detection IC 124 may be arranged outside assuming modularization, or may be fixed so as to contact the upper portion of the support member 131 or the cover 132. A capacitance detection circuit 200 which is a circuit configuration incorporated in the capacitance detection IC 124 is shown in FIG.

  The fixing unit 130 is provided on the atmospheric pressure side of the support member 131 that secures insulation between the diaphragm 111 and the working medium supply assembly 10 and fixes the pressure switch 100 to the working medium supply assembly 10. A cover 132 that seals the housing portion 131b, a plurality of fixing screws 133 that fix the support member 131 and the working medium supply assembly 10, and a plurality of washers 134 that prevent loosening of each of the plurality of fixing screws 133 are provided. .

  The support member 131 has a substantially disk shape, and is formed of, for example, a resin material in order to ensure insulation between the diaphragm 111 and the working medium supply assembly 10. The support member 131 is provided with an opening 131a having a diameter corresponding to the pipe line 11 and an atmospheric pressure side around the opening 131a, and a cylinder that houses the diaphragm assembly 110, the movable electrode 121, and the fixed electrode 122. A housing portion 131b that is a concave portion of the shape, an outer peripheral portion 131c that extends from the housing portion 131b, has a screw hole 131e into which the fixing screw 133 is inserted, and contacts the working medium supply assembly 10, and inside the housing portion 131b. Thus, a recess 131d provided around the opening 131a and in which the O-ring 112 is disposed is formed.

  The cover 132 is disposed on the atmospheric pressure side of the diaphragm assembly 110, the movable electrode 121, and the fixed electrode 122 housed in the housing portion 131b of the support member 131, and seals the housing portion 131b. The cover 132 is formed of, for example, a resin material, fixes the movable electrode 121 and the fixed electrode 122, and performs positioning with respect to the diaphragm 111. The cover 132 may be configured to be fixed to the housing portion 131b by press-fitting, caulking, or an adhesive.

  As an example of a method of attaching the pressure switch 100, first, the diaphragm assembly 110 is assembled. Next, the cover 132 in which the movable electrode 121 and the fixed electrode 122 are fixed is received and fixed in the receiving portion 131 b of the support member 131 on the atmospheric pressure side of the diaphragm assembly 110. The movable electrode 121 and the fixed electrode 122 are connected to the capacitance detection IC 124 via the lead wire 125. Next, the support member 131 is fixed to the working medium supply assembly 10 by a plurality of fixing screws 133 and a plurality of washers 134. Note that this attachment method is not limited, and various methods can be applied depending on the shape of the working medium supply assembly 10, the capacitance detection method, and the like.

  Next, the capacitance detection circuit 200 that is a circuit configuration incorporated in the capacitance detection IC 124 will be described.

FIG. 2 is a block diagram of the capacitance detection circuit 200.
In FIG. 2, the capacitance detection circuit 200 includes an oscillation circuit 210, an oscillation state detection circuit 220, and an output circuit 230. The movable electrode 121 and the fixed electrode 122 are connected as a capacitor that becomes a part of the oscillation circuit 210 of the capacitance detection circuit 200. The oscillation circuit 210 is configured by, for example, an RC circuit or the like, and the oscillation frequency varies due to the variation in capacitance. Therefore, when the diaphragm 111 is displaced and the capacitance varies, the oscillation frequency of the oscillation circuit 210 varies. Next, when the oscillation frequency varies according to the displacement of the diaphragm 111, the oscillation is started or stopped. The output from the oscillation circuit 210 is input to the oscillation state detection circuit 220, and the start or stop of the oscillation described above is detected. The detected detection signal is input to the output circuit 230, amplified, and then output to the outside. Note that the capacitance detection circuit 200 is an example, and it is only necessary to detect the displacement of the diaphragm 111 as the displacement of the capacitance.

  In the conventional capacitance detection pressure switch 100 using the general disk-shaped diaphragm 111 as described above and the pressure sensor configured by the same configuration, the diaphragm 111 used as one electrode, and the diaphragm There is a problem in that the pressure-displacement characteristic of the diaphragm 111, that is, the operation characteristic of the diaphragm 111 is affected by the connection method with the fixed electrode 122 that outputs a signal from 111. In addition, since the diaphragm 111 is slightly deformed, there is a problem that it is difficult to ensure stable conduction between the diaphragm 111 and the fixed electrode 122.

  In order to eliminate the problems of the conventional capacitance detection type pressure switch and pressure sensor, the capacitance detection type pressure switch and pressure sensor of the present invention change the shape of the diaphragm so that the outer circumference of the diaphragm is changed. An electrode contact part for connecting the movable electrode, which is at least one protrusion part extending outwardly in part, is formed. Hereinafter, the characteristics of the capacitance detection type pressure switch and pressure sensor of the present invention when a contact load is applied will be described with reference to FIGS. 3 (a) to 3 (c).

  FIG. 3 (a) is a diagram showing a comparison of characteristics when a contact load is applied between the disk-shaped diaphragm 111 according to the prior art and the diaphragm 300 of the capacitance detection type pressure switch of the present invention. FIG. 3B is a diagram showing a shape when no contact is applied, FIG. 3B is a diagram showing deformation when a contact load is applied, and FIG. 3C is a diagram showing a stress distribution when a contact load is applied.

  3 (a) to 3 (c), the left diagram shows a disk-shaped diaphragm 111 according to the prior art, and the right diagram shows the capacitance detection type pressure switch and the diaphragm of the pressure sensor of the present invention. 300 shows a configuration in which an electrode contact portion 301 for connecting a movable electrode, which is at least one protrusion extending outwardly, is formed on a part of the outer periphery of the diaphragm 300.

  In Fig.3 (a), the arrow has shown the place where a contact load (here 10N) is applied. For example, in the electrostatic capacitance detection type pressure switch 100 according to the prior art of FIG. 1, this contact load assumes that the movable electrode 121 is connected to the diaphragm 111 and some load is applied from the outside. That is, in the conventional diaphragm 111 on the left side of FIG. 3 (a), a load is applied to a part of the outer periphery of the disk-shaped diaphragm, and the capacitance detection type pressure switch of the present invention on the right side of FIG. 3 (a). In the diaphragm 300 of the pressure sensor, it is shown that a load is applied to the electrode contact portion 301 for connecting the movable electrode 121, which is at least one protrusion extending outwardly to a part of the outer periphery of the diaphragm 300. .

  Note that the disk-shaped diaphragm 111 is not actually a constraining structure in which the movable electrode 121 contacts only a part of the circumference of the diaphragm 111, but the movable electrode 121 and other components (for example, a stopper). However, the diaphragm 111 generally has anisotropy due to the rolling direction / warping / bulging, so the circumference is held uniformly. It ’s difficult. Under such conditions, the movable electrode must always be in contact with the diaphragm, and here, the analysis was performed by comparing the degree of influence of local contact with the diaphragm 111 and the present invention.

  Looking at the deformation at the time of applying the contact load in FIG. 3B, in the conventional diaphragm 111 on the left side, the deformation to the bowl portion at the center of the diaphragm 111 that affects the pressure-displacement characteristics of the diaphragm is observed. As can be seen, in the diaphragm 300 of the present invention on the right side, the deformation is limited to the electrode contact portion 301 which is a protrusion, and no influence on the bowl portion is seen.

  Similarly, looking at the stress distribution when the contact load is applied in FIG. 3 (c), the conventional diaphragm 111 on the left side shows the stress at the center of the diaphragm 111 that affects the pressure-displacement characteristics of the diaphragm. In the right diaphragm 300 of the present invention, the stress distribution displacement is limited to the electrode contact portion 301 that is a protrusion, and no influence on the bowl portion is observed.

  As described above, an electrode contact portion 301 for connecting the movable electrode 121, which is at least one protrusion extending outward, is provided on a part of the outer periphery of the diaphragm 300, and the movable electrode 121 is attached to the electrode contact portion 301. By connecting, deformation to the bowl portion at the center of the diaphragm and displacement of the stress distribution that affect the pressure-displacement characteristics of the diaphragm can be suppressed, and stable conduction can be ensured.

  Next, the example of the shape of the electrode contact part provided in the diaphragm of the electrostatic capacitance detection type pressure switch and pressure sensor of this invention is demonstrated.

  FIG. 4A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm 400 formed into a shape in which the electrode contact portion 401 is crimped. 4B is a cross-sectional view taken along IVb-IVb in FIG. 4A, and FIG. 4C is an enlarged view of the movable electrode 421 and the electrode contact portion 401. 4D is an enlarged view showing a state where the movable electrode 421 is inserted into the electrode contact portion 401, and FIG. 4E is a state where the movable electrode 421 is crimped to the electrode contact portion 401. It is a figure which expands and shows.

  4A to 4E, the diaphragm 400 includes an electrode contact portion 401 for connecting the movable electrode 421, which is one protrusion portion extending outward at one location on the outer periphery of the diaphragm 400. Is provided. The electrode contact portion 401 is formed in a shape to be crimped. The electrode contact portion 401 is provided with a through hole 401a in the center, and a movable electrode 421 formed in a shape suitable for caulking as shown in FIGS. 4C and 4D passes therethrough. After being inserted and arranged in the hole 401a, the electrode contact portion 401 and the movable electrode 421 are fixed by caulking as shown in FIG. Two chamfers 401b are provided on the upper side of the electrode contact portion 401 shown in FIG. By providing the chamfer 401b in this way, it is possible to prevent an error in the molding direction at the time of diaphragm molding. Here, two chamfers 401b are provided on the upper side of the electrode contact portion 401, but may be provided on one side or on the lower side. Moreover, it is good also as what provides the same chamfering to embodiment shown to Fig.5 (a) thru | or FIG.7 (c) mentioned later. The effect of the present invention can also be obtained by such a shape.

  FIG. 5A is a diagram showing a reference example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm 500 formed in a shape to which the electrode contact portion 501 is soldered. 5B is a cross-sectional view taken along line Vb-Vb in FIG. 5A, and FIG. 5C is an enlarged view of both the movable electrode 521 and the electrode contact portion 501. FIG. 5D is an enlarged view showing a state in which the movable electrode 521 is inserted into the electrode contact portion 501, and FIG. 5E is a view in which the movable electrode 521 is soldered to the electrode contact portion 501. It is a figure which expands and shows a state.

  5A to 5E, the diaphragm 500 has an electrode contact portion 501 for connecting the movable electrode 521, which is one protrusion portion extending outward at one location on the outer periphery of the diaphragm 500. Is provided. The electrode contact portion 501 is formed in a shape to be soldered. The electrode contact portion 501 is provided with a through hole 501a at the center, and a movable electrode 521 formed in a shape suitable for soldering as shown in FIGS. 5 (c) and 5 (d). After being inserted and disposed in the through hole 501a, the electrode contact portion 501 and the movable electrode 521 are fixed by the solder 502 by soldering as shown in FIG. A thin portion 501b for suppressing heat conduction during soldering is formed near the base of the electrode contact portion 501. The effect of the present invention can also be obtained by such a shape.

  FIG. 6A is a diagram illustrating an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm 600 formed in a shape in which the electrode contact portion 601 is spot-welded. 6 (b) is a cross-sectional view taken along VIb-VIb of FIG. 6 (a), and FIG. 6 (c) is an enlarged view of the movable electrode 621 and the electrode contact portion 601. FIG. 6D is an enlarged view showing a state in which the movable electrode 621 is in contact with the electrode contact portion 601, and FIG. 6E is a state in which the movable electrode 621 is spot welded to the electrode contact portion 601. FIG. 6 (f) is an enlarged view showing a state where the movable electrode 621 </ b> A whose tip is not bent is laser welded to the electrode contact portion 601.

  6A to 6E, the diaphragm 600 has an electrode contact portion 601 for connecting the movable electrode 621, which is one protrusion portion extending outward at one location on the outer periphery of the diaphragm 600. The electrode contact portion 601 is formed in a flat shape that is spot-welded. After the movable electrode 621 having a shape whose tip is bent in an L-shape so as to be suitable for spot welding as shown in FIGS. 6C and 6D, the electrode contact portion 601 is contacted. 6 (e), the electrode contact portion 601 and the movable electrode 621 are fixed by spot welding 602. A thin portion 601b for suppressing heat conduction during spot welding is formed near the base of the electrode contact portion 601. In addition, although fixed by spot welding here, you may fix by the melt-solidified layer 602 by laser welding instead. Further, when laser welding is performed, a movable electrode 621A having a bent end as shown in FIG. 6 (f) may be used and fixed to the electrode contact portion 601 by a melt-solidified layer 602A. Good. The effect of the present invention can also be obtained by such a shape.

  FIG. 7A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and is a plan view of the diaphragm 700 formed into a shape in which the electrode contact portion 701 is fitted into the connector. 7B is a cross-sectional view taken along line VIIb-VIIb in FIG. 7A, and FIG. 7C is a cross-sectional view taken along line VIIc-VIIc in FIG. 7A.

  7A to 7C, the diaphragm 700 includes an electrode contact portion 701 for connecting the movable electrode 721, which is one protrusion portion extending outward at one location on the outer periphery of the diaphragm 700. The electrode contact portion 701 is formed in a shape that fits with the movable electrode 721 through a connector. Here, for example, as shown in FIG. 7C, the electrode contact portion 701 has a protrusion shape 701a bent 90 degrees from the horizontal plane at the tip, and this protrusion shape 701a is, for example, a Giboshi terminal or a Faston terminal (registered). A flat connection terminal such as a trademark), a crimp terminal, or the like is formed, and one of the terminals, which is a movable electrode 721 having a shape corresponding to the protrusion shape 701a, is inserted and fixed. Note that when the movable electrode 721 having such a connector fitting shape is inserted into the protrusion shape 701a, the diaphragm 700 is stressed and easily bent, so a notch 702 is formed near the base of the electrode contact portion 701. May be. The effect of the present invention can also be obtained by such a shape.

  FIG. 8A is a diagram showing an example of the shape of the diaphragm of the capacitance detection type pressure switch of the present invention, and a plurality of leaf spring-shaped electrode contact portions 801a constituting a disc spring shape on the outer periphery of the diaphragm. FIG. 8B is a sectional view taken along line VIIIb-VIIIb in FIG. 8A.

  8A and 8B, the diaphragm 800 is provided with a plurality of leaf spring-shaped electrode contact portions 801a to 801h that form a disk spring shape on the outer periphery of the diaphragm 800. As shown in FIG. 8B, the plurality of leaf spring-shaped electrode contact portions 801a to 801h are formed in a shape bent obliquely upward. Since the electrode contact portions 801a to 801h formed in such a shape have the elastic force of the spring in the horizontal direction, they can be brought into contact with the movable electrode by the elastic force of the spring. In addition, the elastic force of the spring has an effect that when it is attached to the support member 131 shown in FIG. In addition, although the disc spring shape which has a some leaf | plate spring shape was formed here, it is not limited to this, A leaf spring may be formed with another number or a single number. Hereinafter, an embodiment using the diaphragm 800 will be described.

FIG. 9 is a diagram showing a configuration of a capacitance detection type pressure switch 900 according to an embodiment of the present invention.
In FIG. 9, a capacitance detection type pressure switch 900 is mainly characterized by including a disc spring-shaped diaphragm 800 shown in FIG. 8 instead of the general disk-shaped diaphragm 111 shown in FIG. To do. The same components as those of the pressure switch 100 according to the prior art shown in FIG.

  The pressure switch 900 includes a diaphragm assembly 910, a capacitance detection unit 920, and a fixing unit 930 that holds the diaphragm assembly 910 and the capacitance detection unit 920 and fixes them to the working medium supply assembly 10 ′.

  The diaphragm assembly 910 is displaced according to the fluctuation of the pressure of the working medium supplied from the pipe line 11 ′, and is arranged on the side of the pipe line 11 ′ of the diaphragm 800 and the diaphragm 800 and seals the working medium. An O-ring 112 and a diaphragm 113 that is in close contact with the O-ring 112 and seals the working medium are provided.

  As shown in FIG. 8, the disc spring-shaped diaphragm 800 is formed in a disc spring shape in which a plurality of leaf springs are provided on the outer periphery of the diaphragm 800, and is made of a metal material so as to have the elasticity of the spring in the horizontal direction. Is done. The disc spring-shaped diaphragm 800 is fixed by the elastic force of a cylindrical movable electrode 921 described later and a horizontal spring. In addition, the diaphragm 111 is mainly made of a metal having a reversing action, that is, a spring property that performs a snap action. However, when this configuration is applied to a pressure sensor that outputs a pressure measurement value, a snap action is used. Do not use diaphragms.

  The capacitance detection unit 920 is attached to the movable electrode 921 electrically connected to a part of the diaphragm 800, the fixed electrode 122 provided on the atmospheric pressure side of the diaphragm 800, and the diaphragm 800 side of the fixed electrode 122. The insulating coating 123 includes a capacitance detection IC 124 that is electrically connected to the movable electrode 121 and the fixed electrode 122 via the lead wire 125 and detects the capacitance between the diaphragm 800 and the fixed electrode 122.

  The movable electrode 921 is formed of a metal material into a cylindrical columnar shape, and a plurality of leaf spring-shaped electrode contact portions 801a to 801a constituting a disc spring shape provided on the outer periphery of the diaphragm 800 on the inner surface of the cylindrical columnar shape. 801h is contacted. Since the electrode contact portions 801a to 801h have the elasticity of the horizontal spring, the connection between the movable electrode 921 and the electrode contact portions 801a to 801h becomes strong, and stable conduction can be ensured. The movable electrode 921 is connected to the capacitance detection IC 124 via the lead wire 125, whereby the diaphragm 800 forms one electrode of a capacitor in capacitance detection. The cylindrical columnar movable electrode 921 is fixed by press-fitting or insert molding into a receiving portion 931b of a support member 931 described later.

  The fixing portion 930 secures insulation between the diaphragm 800 and the working medium supply assembly 10 ′, and is provided on the atmospheric pressure side of the support member 931 for fixing the pressure switch 900 to the working medium supply assembly 10 ′. A cover 932 that seals the accommodating portion 931b, a plurality of fixing screws 133 that fix the support member 931 and the working medium supply assembly 10 ', and a plurality of washers 134 that prevent looseness of each of the plurality of fixing screws 133. With.

  The support member 931 has a substantially disk shape, and is formed of, for example, a resin material in order to ensure insulation between the diaphragm 800 and the working medium supply assembly 10 ′. The support member 931 is provided with an opening 931a having a diameter corresponding to the pipe line 11 'and an atmospheric pressure side around the opening 931a, and houses the diaphragm assembly 910, the movable electrode 921, and the fixed electrode 122. An accommodating portion 931b that is a cylindrical recess, an outer peripheral portion 931c that extends from the accommodating portion 931b, has a screw hole 931e into which the fixing screw 133 is inserted, and contacts the working medium supply assembly 10 ', and the accommodating portion 931b A recess 931d is provided inside the opening 931a and in which the O-ring 112 is disposed. The cylindrical movable electrode 921 described above is fixed to the housing portion 931b by press-fitting or insert molding.

  As described above, the effect of the present invention can also be obtained by the capacitance detection type pressure switch 900 of the present embodiment.

  Also, in this embodiment, if the diaphragm of the slow action is used instead of the snap action, and the output signal of the capacitance detection circuit is changed to output the linearly changing capacitance as it is, this It is also possible to apply the configuration of the embodiment to a pressure sensor.

  As described above, according to the capacitance detection type pressure switch and pressure sensor of the present invention, the electrode for connecting the movable electrode, which is at least one protrusion extending outwardly to a part of the outer periphery of the diaphragm By providing a contact part and connecting a movable electrode to this electrode contact part, it is possible to suppress deformation to the bowl part at the center of the diaphragm and displacement of the stress distribution that affect the pressure-displacement characteristics of the diaphragm. Stable conduction can be ensured.

100, 900 Pressure switch 110, 910 Diaphragm assembly 111, 300, 400, 500, 600, 700, 800 Diaphragm 112 O-ring 113 Diaphragm 120, 920 Capacitance detector 121, 321, 421, 521, 621, 621A, 721 , 821, 921 Movable electrode 122 Fixed electrode 123 Insulating film 124 Capacitance detection IC
125 Lead wire 130, 930 Fixing part 131, 931 Support member 132, 932 Cover 133 Fixing screw 134 Washer 200 Capacitance detection circuit 210 Oscillation circuit 220 Oscillation state detection circuit 230 Output circuit 301, 401, 501, 601, 701, 801 Electrode contact area

Claims (6)

When the pressure of the working medium supplied from the pipe is displaced according to the fluctuation of the pressure and the pressure of the working medium from the pipe is less than a set value, the pipe is formed in a bulging shape downward. A diaphragm that performs a snap action that reversibly inverts from a shape that bulges downward to a shape that bulges upward due to the pressure of the working medium when the pressure of the working medium from is higher than a set value ;
A movable electrode electrically connected to the diaphragm;
A fixed electrode provided on the atmospheric pressure side facing the pipe line of the diaphragm;
An insulating coating that ensures insulation between the fixed electrode and the diaphragm;
The diaphragm is displaced by a change in pressure of the working medium, and the displacement is detected as a change in capacitance between the diaphragm connected to the movable electrode and the fixed electrode. A capacitance-sensing pressure switch configured to detect the pressure of the working medium based on:
An electrostatic capacitance detection type pressure switch, wherein an electrode contact portion for connecting the movable electrode, which is at least one protrusion portion extending outwardly, is formed on a part of the outer periphery of the diaphragm. The electrode contact portion is provided with a through hole in a central portion, and at least one chamfer is provided on one side, and is formed into a shape that is caulked with the movable electrode. The capacitance detection type pressure switch according to claim 1. 2. The capacitance detection type pressure switch according to claim 1 , wherein a thin portion is formed near a base of the electrode contact portion and is formed in a shape that is spot-welded to the movable electrode. 2. The capacitance detection type pressure switch according to claim 1 , wherein a thin portion is formed near a base of the electrode contact portion , and is formed into a shape welded to the movable electrode. The tip of the electrode contact portion is formed with a projection shape bent 90 degrees from a horizontal plane at the tip, and the electrode contact portion is formed in a shape to be fitted to the movable electrode and a connector. 1. The capacitance detection type pressure switch according to 1.   The static contact according to claim 1, wherein the electrode contact portion is formed in a disc spring shape in which a leaf spring is provided on an outer periphery of the diaphragm, and is connected by the elastic force of the movable electrode and the disc spring. Capacitance detection pressure switch.